Universal clamp with pivoting arm retention means

ABSTRACT

A manually operated toggle type clamp suitable for clamping a work piece to a machine bed or the like and having retention means suitable for stopping and holding the clamp in a predetermined open position. The retention means is mounted on an arm initially pivotally attached to the base of the clamp with complementary engaging means attached to the handle link. When the clamp is set up, the retention means is adjustably positioned as desired and welded to the base. At the same time, the clamp support plates are adjusted and welded to the base in the appropriate position to determine the fully closed position. The clamp is then ready for repeated operation from the adjusted fully closed to the final pre-determined open position with assurance that the clamp is rigidly mounted upon the base with the required closed work clamping position, and the desired opening stroke ending with a hold open retention.

United States Patent [191 Sendoykas et al.

[ Aug. 27, 1974 UNIVERSAL CLAMP WITH PIVOTING ARM RETENTION MEANS [73] Assignee: Dover Corporation (De-Sta-Co.

Division), Detroit, Mich.

22 Filed: Aug. 28, 1972 211 Appl. No.: 284,038

[52] U.S. Cl 269/228, 74/526, 269/94, 269/285 [51] Int. Cl B251) 5/12 [58] Field of Search 269/91, 94, 93, 201, 228, 269/285; 74/526; 292/76 Primary Examiner--Roy Lake Assistant Examiner-Neil Abrams Attorney, Agent, or Firm-Farley, Forster and Farley [57] ABSTRACT A manually operated toggle type clamp suitable for clamping a work piece to a machine bed or the like and having retention means suitable for stopping and holding the clamp in a pre-determined open position. The retention means is mounted on an arm initially pivotally attached to the base of the clamp with complementary engaging means attached to the handle link. When the clamp is set up, the retention means is adjustably positioned as desired and welded to the base. At the same time, the clamp support plates are adjusted and welded to the base in the appropriate position to determine the fully closed position. The clamp is then ready for repeated operation from the adjusted fully closed to the final pre-determined open position with assurance that the clamp is rigidly mounted upon the base with the required closed work clamping position, and the desired opening stroke ending with a hold open retention.

8 Claims, 6 Drawing Figures PATENTED M1927 I374 HERE-N3 FIG.3

UNIVERSAL CLAMP WITH PIVOTING ARM RETENTION MEANS BACKGROUND OF THE INVENTION Prior art manual clamps with toggle linkage of the type disclosed in this application are generally used for clamping a work piece to a fixture, machine bed or the like. The clamps comprise a clamping arm pivoted on a base and a toggle mechanism actuated by a handle to swing the clamping arm into and out of clamping position. The engagement of the clamping arm with the work piece in combination with the toggle mechanism provides a locked stop and hold for the clamp when in fully closed position. When the clamp is released, the handle and toggle mechanism swing the clamping arm out of the way of the work piece with both the handle and clamping arm swinging about separate pivots usually more than 180. With the base of the clamp mounted horizontally, the weight of the handle and clamp arm retains the clamp in the fully open position. Some prior art clamps have also utilized a supplemental retainer on the outside of the clamping mechanism adjacent the base to more positively retain the clamp in the fully open position. Such retainers are limited by a low mechanical advantage when engaged and may not .be operative if outside constraints prevent a full opening of the clamp.

SUMMARY OF THE INVENTION The present invention provides a relatively long separate retention arm pivotally attached to the base and support link of the clamp and extending out from under the clamp to support retention means adapted to engage complementary engaging means which in turn are attached to the handle link. When the clamp is initially installed by the user, the support plates of the clamp are welded or otherwise permanently secured to the base in an angular position that determines the fully clamped position of the clamp. At this time, the retention arm is properly positioned with respect to the base and welded or otherwise permanently secured to both the base and the support plates. This construction provides integral support plate and base rigidity for the clamp fully, with an adjustably predetermined final open position which may be limited to only the necessary opening stroke and thereby avoid unnecessary lost motion overtravel. The retention arm may be so constructed that the possible range of final open positions is greatly enlarged by a retention arm and base structure reversible with respect to the remainder of the clamp mechanism, or alternate retention arms may be provided for the same purpose. Thus, the clamp may be located in any angular position relative to overhanging gravity forces on the linkage, with assurance that when the handle is pulled and the clamp opened to the desired clearance position, the clamp will be retained in the final open position.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the clamp with the retention means disengaged;

FIG. 2 is a side view of the clamp with the retention means engaged;

FIG. 3 is a fragmentary view of the clamp taken in the direction 3 of FIG. 2;

FIG. 4 is a side view of the clamp similar to FIG. 2 with the base and retention arm in reversed position;

FIG. 5 is a side view of an alternate form of the clamp and retention means; and,

FIG. 6 is an end view of the alternate clamp of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1 and 2, the clamp includes two parallel support plates 10 forming initially adjustable extensions pivotally mounted on base 36 and a clamping arm 12 pivotally attached at 14 between the support plates. The clamping arm 12 may have a clamping extension 16 welded to its nose 18. A handle link 20 includes two arms 22 which straddle the support plates 10 and are pivotally joined to the support plates by a pivot 24. The two arms 22 are joined together in the upper portion of the handle link 20 and a handle 26 may be suitably attached to the handle link 20 at 28.

Lying between the handle link arms 22 and above the support plates 10 are a pair of toggle links 30 which in turn are pivotally attached to the: handle link arms by a cross pin 32. The toggle links 30 are also pivotally attached by a cross pin 34 to the clamping arm 12. The entire clamp mechanism is mounted on a base 36 extending between support plates 10 and pivotally attached thereto by the pivot 24. As shown more clearly in FIG. 3, the handle link arms 22 enclose therebetween the support plates 10, base 36 and a stop arm or retention arm 38 which is also pivotally attached by the pivot 24. The base 36 is recessed! at 40 to provide access for the complementary recessed portion 42 of the retention arm 38.

Referring to FIGS. 1 and 2 the upper end of the retention arm 38 has a tongue 44 fastened to the retention arm 38 by machine screws 46 or other suitable means. The tongue 44 has a rounded end 48 adapted to engage a resilient clip 50, so shaped at 52 to retain the tongue 44 as shown in FIG. 2. The clip in turn is attached to the handle link 20 by the resilient cushioning block 54 and machine screws 56 or other suitable attachment means. The cushioning block 54 comprises two metal plates 58 having a rubber block 60 bonded therebetween. Thus, upon engagement as shown in FIG. 2, the tongue 44 will slightly compress the rubber block 60 thereby providing a cushioned snap engagement.

Prior to set up the support plates 10 and retention arm 38 are rotatably free about the pivot 24 with respect to the base 36. When the clamp is installed, the support plates 10 are welded or otherwise permanently secured as shown by the weld 62 joining one of the support plates 10 to the base 36. The angular position of the support plates 10 with respect to the base 36 will determine the fully closed position of the clamp relative to the base 36. The retention arm 38 is also welded or otherwise permanently secured to the other support plate 10 at 64 and welded or permanently secured to the base 36 at 66. Thus, upon installation, the support plates 10, base 36 and retention arm 38 will form a rigid structure upon which the handle link arms 22 are free to rotate about the pivot 24. The angular range of adjustment for the retention arm 38 is determined by the portion 68 of the clamping arm extending around the pivot 14 when the clamp is fully closed and the angular position of the support plates 10 with respect to the base 36. This range is extended by the elbow 70 of the retention arm 38 which allows the alternate position 72 shown in phantom in FIG. 1 wherein the elbow 70 of the retention arm 38 is relatively close to the clamping arm end 68. Position 72 of the retention arm 38 provides the minimum final open position for the handle 26. The relatively long arm 38 provides a high mechanical advantage for retention of the handle link and clamp regardless of the angular position of the arm 38.

On the other hand, the maximum opening range with the retention arm 38 may be extended by providing certain features on the retention arm 38 and reversibility for the base 36. The retention arm 38 provides complementary mounting sockets 74 and 76. As shown in FIGS. 1 and 2, the socket 74 has the tongue 44 mounted therein. Alternately, as shown in FIG. 4 the tongue 44 is mounted in socket 76 and the retention arm 38 is reversed in position on pivot 24 as shown to increase the angular range possible for the final open position. In order to accomplish this, the case 36 is also reversed on pivot 24 in order that the complementary recessed portions 40 and 42 may properly engage between plates 10. As a further alternative, a tongue and groove configuration of the base 36 and arm 38 might be utilized to allow reversible engagement of the retention arm 38 at the pivot 24 without requiring reversibility of the base 36. Thus, a variety of bases and mounting arms suitable for pivotable attachment at pivot 24 may be provided for selection by the user.

In FIGS. and 6 an alternate form of the clamp with modified arms 122 and base 136 is shown. Elements substantially similar to those in FIGS. 1-4 are identified with the same numbers having the prefix l. The modified retention arm 138 of the clamp comprises two arms 180 and 182 joined by a center section 1184. The arms 180 and 182 are pivotally attached on pivot 124 between the arm 122 and support plate 110 on each side as shown in FIGS. 6. A tongue 144 is attached to the center section 184 by screws 146 or other suitable means and rests against a lip 186 extending from the center section 184. The lip 186 assures that the tongue 144 will always be properly supported for engagement with the clip 150 and against the cushioning block 154. This particular form allows the retention arm to be economically manufactured as a stamping although it may be cast or forged to include the tongue 144 as an integral part. The twin arms 180 and 182 allow the retention arm 138 to be positioned straddling the pivot 114 for very limited angular opening movement or posi tioned as shown for very large angular opening movement. As above the retention arm 138 may be welded in position after the final adjustment has been determined.

We claim:

I. In a toggle clamp having mounting base, clamp arm, actuating handle, and toggle linkage elements pivotally interconnected, the improvement comprising a mounting plate intermediate said elements and base pivotally adjustable relative to said base, an adjustably mounted auxiliary stop arm pivotally adjustable relative to said base on a common axis with said mounting plate on said base, means for holding said stop arm in adjusted fixed relation to said base, means for holding said plate in adjusted fixed relation to said base, one of said elements being movable toward said stop arm upon the release opening of said clamp, and interengaging stop and retention means cooperatively mounted on said last element and stop arm to provide desired limited opening and retention for said clamp, whereby said clamp arm may be first conveniently adjusted to desired clamping position through. relative pivotal movement of said plate and base prior to fixing their relation and second conveniently adjusted to desired limited open position through relative pivotal movement of said stop arm and base prior to fixing their relation and wherein said stop arm after adjustment is permanently fixed in position relative to said base element.

2. The clamp of claim ll, wherein a portion of said interengaging means is attached to the handle element.

3. The clamp of claim 1, wherein said interengaging means includes a defiectable spring providing automatic snap action engagement upon opening actuation of said handle element and automatic yieldable release upon application of a predetermined closing force to said handle element.

4. The clamp of claim 3, wherein said interengaging means includes a resilient cushioning stop.

5. The clamp of claim 1, wherein the stop arm includes an elbow shape to accommodate adjustment to a small minimum opening movement.

6. The clamp of claim 5, wherein the stop arm element is adapted for reversible attachment to accommodate adjustment to a large maximum opening movement.

7. The clamp of claim 1, wherein the stop arm and handle element are initially pivotally attached to the base element on a common pivotal axis and said interengaging means includes a portion on said handle element radially spaced from said pivotal axis in the order of at least one-half of the length of said handle element.

8. The clamp of claim 7, wherein said stop arm is welded in fixed relation to said base element after initial pivotal adjustment. 

1. In a toggle clamp having mounting base, clamp arm, actuating handle, and toggle linkage elements pivotally interconnected, the improvement comprising a mounting plate intermediate said elements and base pivotally adjustable relative to said base, an adjustably mounted auxiliary stop arm pivotally adjustable relative to said base on a common axis with said mounting plate on said base, means for holding said stop arm in adjusted fixed relation to said base, means for holding said plate in adjusted fixed relation to said base, one of said elements being movable toward said stop arm upon the release opening of said clamp, and interengaging stop and retention means cooperatively mounted on said last element and stop arm to provide desired limited opening and retention for said clamp, whereby said clamp arm may be first conveniently adjusted to desired clamping position through relative pivotal movement of said plate and base prior to fixing their relation and second conveniently adjusted to desired limited open position through relative pivotal movement of said stop arm and base prior to fixing their relation and wherein said stop arm after adjustment is permanently fixed in position relative to said base element.
 2. The clamp of claim 1, wherein a portion of said interengaging means is attached to the handle element.
 3. The clamp of claim 1, wherein said interengaging means includes a deflectable spring providing automatic snap action engagement upon opening actuation of said handle element and automatic yieldable release upon application of a predetermined closing force to said handle element.
 4. The clamp of claim 3, wherein said interengaging means includes a resilient cushioning stop.
 5. The clamp of claim 1, wherein the stop arm includes an elbow shape to accommodate adjustment to a small minimum opening movement.
 6. The clamp of claim 5, wherein the stop arm element is adapted for reversible attachment to accommodate adjustment to a large maximum opening movement.
 7. The clamp of claim 1, wherein the stop arm and handle element are initially pivotally attached to the base element on a common pivotal axis and said interengaging means includes a portion on said handle element radially spaced from said pivotal axis in the order of at least one-half of the length of said handle element.
 8. The clamp of claim 7, wherein said stop arm is welded in fixed relation to said base element after initial pivotal adjustment. 